High-voltage switch



June 17, 1952 1 C, HART 2,601,138

HIGH-VOLTAGE SWITCH `lune 17, 1952 L.. c. HART HIGH-VOLTAGE SWITCH 2 SHEETS--SHEET 2 Filed March 12, 1949 w fm fw of@ 7 Q Q 6 0 2 w j w ww w HHIIIIIIIIHIIIIIIHHIIHHIJHHHHIIUHHMWMUHHUHHHH'VIIIMIIIIHHHH w k? rial, KV

IN VEN TOR.

C. Hari,

Patented June 17, 1952 UNITED STATES ETENT FFICE HIGH-VOLTAGE SWITCH Application March 12, 1949, Serial No. 81,048

11 Claims.

rlhis invention relates to high voltage switches and more particularly to high voltage switches of the type employed in power distribution circuits, which in addition to operating as disconnecting or isolating switches for certain circuit sections are also capable of interrupting substantial currents in the form of line charging currents, transformer magnetizing currents, energy loads and the like.

It will be understood by those skilled in the art that high voltage switches are extensively employed, particularly in outdoor switching stations for isolating sections of transmission lines and the like under certain conditions. Such high voltage switches are generally air break switches which are crank operated through a manual crank mechanism or the like to isolate desired sections and insert other sections. Such air break 'switches heretofore have generally been provided with arcing horns so as to interrupt transformer magnetizing currents and the like. In recent years the line charging currents have become so large that such air break switches have not been too satisfactory for interrupting such line charging currents and it would be desirable to provide a high voltage air break switch capable of satisfactorily interrupting such line charging currents under all conditions while still conforming in general to the configuration of the well-known high voltage air break switch so extensively employed for these purposes.

Accordingly it is an object of the present invention to provide a new and improved high voltage air break switch.

It is another object of the present invention to provide a new and improved high Voltage air break switch capable of interrupting line charging currents under substantially all conditions of operation.

Still another object of the present invention is to provide a new and improved high voltage air break switch having a circuit interruptor built intoA the stationary arcing horn of such switch,

It is a further object of the present invention to provide an improved high voltage air break switch including means defined in a necessary part of such switch for interrupting any arcs which might occur due to opening of said switch. t It is a further object to provide an improved circuit interrupter in which a movable contact in the form of a rod or tube is propelled freely during a circuit interrupting operation without being attached to any driving or pulling means therefore.

Further objects and advantages of the present invention will become apparent as the following description proceeds, and the features of novelty which characterize the invention will be pointed out with particularity in the claims annexed to and forming a part of this specification.

For a better understanding of the present invention, reference may be had to the accompanying drawings in which:

Fig. 1 is an elevational view of a high voltage air break switch embodying the present invention, which switch conforms in most particulars to one standard high voltage air break switch available on the market today;

Fig. 2 is an enlarged sectional view of a portion of Fig. l to illustrate the details of the interrupter disposed in the stationary arcing horn of the air break high voltage switch;

Fig. 3 is a sectional View taken on line 3 3 of Fig. 2';

Fig. 4 is an enlarged sectional view taken on line 4 4 of Fig. 2; and

Fig. 5 is an enlarged sectional view somewhat similar to Fig. 2 showing a modification of the present invention.

It will be understood that high voltage air break switches are generally employed for multi-pole operation although they might equally well be employed for single-pole operation. To simplify the drawings only a single pole of the switch is illustrated. In a multi-pole switch additional units identical with that shown in Fig. l of the drawings would be provided with links interconnecting the operating mechanisms to insure simultaneous operation of the switch blades.

Referring now to Fig. 1 of the drawings there is illustrated a switch generally indicated at l0 which may comprise any form of high voltage air break switch but which has been specifically illustrated as of the type of high voltage switch disclosed in copending Hart and Seaman application, Serial No. 786,890, iiled November 19, 1947, now PatentNo.2,51l,263,July 4, 1950 and assigned to the same assignee as the present application. This highvoltageswitch Ill comprises a base member H formed of channel iron or anyothersuitable material which will provide a rigid member for supporting the switching contacts and operating means. As illustrated the base H is disposed in a horizontal position. It should be understood, however, that this might equally well be disposed in a vertical position and the illustrated position is by way oi example only. Secured to the base Il are a pair of iixed or stationary insulors l2 and i3 mounted in spaced relationship on the insulator H, and a movable insulator I4 positioned between the xed insulators I2 and I3. The insulators I2 and I3 are provided with suitable means for securing them to the base II. The insulator I4 on the other hand includes a downwardly extending shaft I5 which is adapted for rotation in a suitable bearing I6 mounted on the base I I. The end of the shaft I5 depending below the base II is provided with a hexagonal end I5a which may be engaged by a suitable manual operating lever or the like to cause rotation of the insulator` I4. Preferably the bearing and shaft depending below the base II are provided with a suitable sleet hood I1.

For the purpose of operating the switch I as a multipole switch one or more crank arms I8 may ,i

be provided to rotate with the insulator shaft I5. As illustrated the crank arm I8 is provided with an operating eye I9 which may be connected to suitable rods for interrelating the operation of the plurality of poles or" the multi-pole switch f to insure simultaneous operation thereof. It will be understood that where a single pole switch is employed the crank arm I8 may be dispensed with. Also instead of applying a crank to the hexagonal extension Ia, power for operating the switch may be applied through a suitable link connected to the crank I2 as will be understood by those skilled in the art.

In order to support electrical conductors which together with the switch IU comprise the circuit to be controlled, the insulator I2 has mounted thereon a hinged base and terminal support 2l while the insulator I3 has mounted thereon a contact support 22. It will be understood that the supports 2l and 22 are suitably fastened to their associated insulators I2 or I3 in any conventional manner. Mounted on the support 22 is a stationary contact means or assembly generally designated at 23 and described in greater detail hereinafter. is not visible in the drawings since it is covered by a sleet hood 24 preferably formed of bronze or the like. It will be understood that the sta-- tionary contact may comprise any suitable contact capable of carrying the currents at the high voltages involved, and in general preferably comprises spring biased contact jaws for engaging and receiving therebetween the blade-like contact portion 25 of a switch blade 2 The support 22 also includes an extension 21 to which a suitable terminal 2S may be bolted or otherwise secured, which terminal is electrically connected to a suitable conductor 29.

Also mounted on the support 22 is a stationary arcing horn generally designated as which in the illustrated embodiment extends vertically for a substantial distance above the support 22 and which cooperates with a bifurcated arcing horn SI forming an extension of the switch blade 26. This bifurcated arcing horn 3| is movable with the switch blade and is henceforth designated as the movable arcing horn 3I to distinguish it from the stationary arcing horn 35. The support 22 further includes a contact base guide 33 for supporting and guiding the movable contact 25 fastened to the end of the switch blade 26 in its initial movement during the circuit opening operation and in its nal movement during the circuit closing operation, when the switch blade moves endwise along its longitudinal axis, thereby guiding the blade during this movement.

As has been mentioned above, the high voltage switch IG is an isolating switch rather than a circuit breaker in the sense that it is normally not required to interrupt high currents. How- The stationary contact itself .i

ever, it is occasionally necessary to interrupt energy loads, transformer magnetizing currents and line charging currents which in prior art ar rangements would be interrupted at the arcing horns 33 and 3l rather than at the current carrying contacts comprising the switch blade 25. As will become apparent from the following description, however, the switch III of the present invention includes within the stationary arcing horn 3B interrupting means capable of interrupting high line charging currents which heretofore could not be satisfactorily interrupted by air break switches of the type disclosed.

Preferably the switch I0 is of the type in which the switch blade moves along its longitudinal axis both during the initial opening movement and the final closing movement thereof and for the rest of the time pivots or swings in an arc about an eiectivc pivot. To accomplish this the support 2I which is in the form of a casting suitably bolted or fastened to the stationary insulator I2 has associated therewith a plurality of links 35, 35 and 31. The lower ends of the links 35 and 35 are pivoted to spaced points on the support 2l and the upper ends thereof are pivoted to spaced points on the link 31. Actually the link 31 is provided with an extension connected to the switch blade 26. A suitable crank 39 fastened to the rotatable insulator I4 is connected by means of a connecting rod 43 with the link 31 so that upon rotation of the insulator I4 the particular arrangement of the links 35. 3G and 31 causes the switch blade 26 to move substantially along its longitudinal axis when in a position closely associated with the stationary contact 23 and pivotal arcuate movement thereof for the major portion of the switch movement. Also associated with the stationary support 2I is a terminal extension 40, to which may be bolted or otherwise secured a terminal 4I connected to the end of an electrical conductor 42. It will be apparent that the switch I provides the controlled path between the conductors 29 and 42.

The arrangement described thus far forms no part of the present invention and is fully disclosed and claimed in the co-pending application referred to above.

In accordance with the present invention the stationary arcing horn 30 is considerably different from stationary arcing horns employed heretofore in that it has disposed therein a circuit interrupter capable of interrupting line charging currents of considerable magnitude. As illustrated the stationary arcing horn 3D instead of comprising a conventional conducting rod or tube essentially comprises an upper conducting portion 45 in the form of a tube which is the portion of the stationary arcing horn electrically engaged by the movable arcing horn 3|. The lower portion of the stationary arcing horn 30 comprises a stationary insulating tube 46 preferably formed of a weather-proof insulating material which effectively insulates the conducting tube 45 from the stationary contact 23 of the switch I2. As illustrated the stationary contact 23 is provided with a tubular extension or housing 41 terminating at its upper end in an annular' Contact 48. The tubular extension or housing 41 is preferably formed of copper or other good conducting material so as electrically to connect the annular contact 48 with the stationary contact 23 of the switch IU. The insulating tubular member 45 is concentrically disposed with respect to the conducting member 41 and is shown as also threadedly engaged with the conducting portion 45 of the arcing horn 30. As illustrated the exterior surface of the stationary arcing horn 38 is of generally smooth configuration at the junction points between the conducting member 41, the insulating tubular member 46 and the conducting member 45. At the lower end of the tubular conducting member 45 and electrically connected thereto is a stationary con- 'tact 56 of annular configuration. These annular contacts 48 and 58 are separated by a tubular member 45a formed of a gas evolving insulating material such as horn fiber or the like from which an arc extinguishing gas is evolved when subjected to the heat of an arc. Member 46a is illustrated as having a bore of a diameter corresponding to the diameter of the bores in the annular -contacts 48 and 58.

In accordance with the present invention the contacts 48 and 50 are adapted to be electrically interconnected by a movable interrupting contact 5| preferably in the form of the light conducting tube such as an aluminum or copper tube, the ends of which are disposed within the annular contacts 48 and 50. Actually the movable contact 5| is of somewhat smaller diameter than the diameter of the bores within the annular contacts 48 and 56 and the tube 46a, but in view of the high voltages involved a current will readily now across the small gap between the movable contact 5| and the annular contacts 48 and 5!) when a current path must be established therethrough.

For the purpose of increasing the interrupting capacity at low currents the movable contact 5| has preferably attached to the lower end thereof an insulating follow rod 52 preferably threadedly connected thereto as indicated at 53. If desired this follow rod may also be formed of a gas evolving insulating material. As illustrated the lower end of the follow rod 52 is supported on a movable platform 54 which in turn is supported upon a compression spring 55 disposed in the lower portion of the conducting housing 41 and resting on a suitable member such as the base of the housing 41. In order to hold the compression spring 55 in a charged condition there is provided a bell crank 56 including arms 56a and 56h pivotally mounted as indicated at 51 to the lower portion of the housing 41. The arm 56a of the bell crank 56 is connected by means of a con- .Y

necting rod 58 with the platform 54 so that when rotated in a clockwise direction about the pivot 51 the spring 55 is stressed due to downward movement of the platform 54. A suitable latch 60 is adapted to engage the free end of the arm 56a of the bell crank 56 and hold the compression spring in a charged condition. As illustrated the latch 6|) is biased into its latching position by means of a tension spring 62. The arm 56D of the bell crank 56 extends into the path of movement of the movable contact 25 of the switch blade 26. A suitable compression spring 63 is disposed between the arm 56h of the bell crank 56 and the housing 41 so as to tend to bias the arm 56h when the latch 60 is not in latching engagement into the path of the movable contact 25. With this arrangement it will be apparent that when the contact 25 moves toward the stationary contact 23 during the final portion of the closing operation, the compression spring 55 is stressed until the latch 60 is effective to restrain the spring 55 in the condition shown in Fig. 2 of the drawings. Even if the movable contact 25 were now moved along its longitudinal axis away from the stationary contact 53 the 6 compression spring would remain stressed as shown by virtue of the latch Bil.

From the above description it will be apparent that when the switch I0 is in the closed position the current path will be through the movable contact 25 and the stationary contact 23. A parallel path will be provided through the movable arcing horn 3 I, the tubular conducting member 45, the annular contact 56, the movable contact rod or tube 5|, the annular contact 48 and the tubular conducting member or housing 41. However by virtue of the relatively poor contact between the annular contacts 48 and 50 and the movable contact rod or tube 5| no substantial amount of current will be carried by this path since the other path has substantially zero resistance. It will be apparent however that upon separation of the movable contact 25 from the stationary contact 23 that the only current path is through the movable contact rod or tube 5| and he remainder of the stationary arcing horn 38 to the movable arcing horn 3 For the purpose of interrupting the circuit within the arc extinguishing chamber dened by the bore of the tubular member 46c there is provided a tripping mechanism for releasing the latch 63 prior to separation of the movable and stationary arcing horns 3| and 3! respectively. To this end there is disposed adjacent the upper end of the stationary arcing horn 30 a trip lever (i5 supported on a trip shaft 66 which is journaled in the tubular member 45 so as not to interfere with movement of the movable arcing horn 3| except only by engagement with the trip lever 65. The shaft 66 is provided with a crank arm 61 which is connected by a flexible cord 68 of insulating material with the trip latch 60. A suitable pulley 59 pivotally mounted at 10 to the housing 41 guides the insulating cord 68 in its latch release movement. As is best shown in Fig. e the trip lever 65 protrudes through a narrow elongated opening 1| in the tubular member 45 so as to be engaged by one of the bifurcations of the movable arcing horn 3|. A suitable light tension spring 12 holds the trip lever 65 in the position shown in Fig. 4, thereby maintaining the cord 68 in a taut condition. During the opening operation of the switch the trip lever 65 is moved upwardly applying a tension to the cord 68 with the resultant release of the latch 60. Such a release of the latch will cause the tubular movable contact 5| to be driven upwardly so as to draw an arc between the lower end thereof and the annular contact 48. This arc will be confined within an annular space between the insulating follower rod 52 and the bore of the tubular member 46a. The heat of this arc will cause an arc extinguishing gasto be evolved from the adjacent surfaces of the members 46a and 52 with the result that the arc is rapidly extinguished within a fraction of the cycle of the alternating current and before the movable contact 5| returns by gravity to its position on the platform 54. During the circuit closing operation one of the bifurcations of the movable arcing horn 3| will engage the trip lever and .bias it downwardly against the tension of light spring 12, but since the insulating cord 68 will merely slacken, no effect by such actuation of trip lever 65 is transmitted to the latch 68 during the circuit closing operation.

For the purpose of venting the arc gases formed during the arc interrupting operation a suitable vent 13 is provided in the tubular member 45. This vent is disposed in a position so as not to interfere with the movement of the movable arcing horn 3| and is preferably directed downwardly to prevent rain or sleet from entering the same.

In view of the detailed description included above the operation of the switch l of the present invention will be understood by those skilled in the art. Briefly with the switch closed as indicated in Figs. l and 2 and the compression spring 55 charged or compressed as indicated in Fig. 2, a circuit opening operation will comprise movement of the movable contact along its longitudinal axis away from the stationary contact 23 for a predetermined distance after which pivotal movement of the vswitch blade 26 occurs. During such switch opening operation, upon separation of the contacts 23 and 25, the current is transferred to a path comprising the arcing horns 30 and 3| which includes a path through the movable contact 5|. Before an external gap is produced between the arcing horns 30 and 3| the trip lever is actuated with the subsequent release of the trip latch 60, and the energy stored in the spring 55 is rapidly released to drive the movable contact 5|, which is freely movable without any restraint whatever, somewhat in the nature of shooting an arrow or missile to produce an arc gap between the movable contact 5| and the annular contact 48. This arc is rapidly extinguished even before the arcing horns 30 and n 3| completely separate to introduce the external isolating gap. The movable contact 5| will immediately fall by gravity to its initial position supported on the platform 54. However, no energy will now be stored in the spring 55. reclosing of the switch l0 the spring 55 will be recharged as the switch blade 25 pushes the end of the bell crank arm 56o until the latch 60 is effective to restrain the bell crank in the position shown.

Under certain load conditions the arc interrupting function may not be completed before the arcing horns separate and an external arc may be drawn to assist in the circuit interrupting function. It may be desirable to employ resilient auxiliary arcing horns in such case which spring away from the stationary horns to provide a fast break somewhat of the nature employed in some conventional load break switches. The arcing contacts within the stationary arcing horn are capable of controlling any external arc which is formed.

It will be understood that various modifications of the arrangement described can readily be made with respect to many features thereof.

For example, the insulating follow rod 52 might be dispensed with under certain conditions and the arc interrupted solely by the gas evolved from the walls of the tube 46a. Also modifications in the latching means may be made and the latch cord |58 might be disposed in a suitable housing so that it will not be adversely affected by weather conditions and the like. In Fig. 5 of the drawings there is illustrated a modification of the stationary arcing horn 30 which still embodies all of the principles of the present invention.

Referring now to Fig. 5 of the drawings there is illustrated a stationary arcing horn, very similar to the arcing horn 30, generally designated at which is supported with the support 22 on the stationary insulator 3. The corresponding parts of Fig. 5 are designated by the same reference numerals as in the preceding gures. The movable contact 25 of the switch blade 28 is illustrated as in its fully closed po- Upon y sition. The interrupter within the stationary arcing horn 80 is especially designed so that no gases can escape from the lower end thereof thereby improving the interrupting abilit'y thereof As illustrated the lower end of the stationary arcing horn 80 comprises a sealed housing 8| preferably in the form of a casting of conducting material such as copper or bronze which may be formed as an integral part of the support 22. As illustrated the upper end of the casting or housing 8| is provided with two openings 83 and 84 for receiving therein the lower ends of large tube 85 and small tube 86 respectively. The tube 86 is merely a housing for a trip rod 81, which trip rod 81 extends down into the housing 8| to actuate a suitable trip latch to be described hereinafter. The tube 85 on the other hand is an arc extinguishing tube provided with a bore 85a, the walls of which are preferably defined of gas evolving insulating material for evolving a gas when subjected to the heat of an arc. Preferably the tube 85 is provided with a weatherproof external surface in the manner disclosed in the preceding embodiment.

For the purpose of controlling the circuit interrupting operation of the interrupter defined in the stationary arcing horn 80 the housing 8| is provided near the lower portion thereof with a. platform 90 having suitable openings 9| and 92 therein for accommodating the trip rod 81 and a spring charging rod 93. As illustrated a compression spring 94 has its lower end resting on the platform 90 with its axis parallel to the axis of the opening 92. A suitable member or platform 95 attached to the upper end of rod 93 is adapted to engage the upper end of the compression spring 94. The rod 93 is guided for vertical movement by a suitable guide member 96 which may comprise a roller suitably supported within the housing 8| if desired. The lower end of the rod 93 is provided with a latching member 91 engageable with a trip latch 98 pivotally mounted as indicated at 99 within the housing 8| beneath the platform 92. The trip rod 81 is suitably connected to the trip latch 98 as by extending through an opening therein and provided at its lower end with a suitable enlargement 81a which will not pass through such opening in the trip latch 98. With this arrangement upward movement of the trip rod 81 will release the trip latch 98, but downward movement of the trip rod 81 will cause no movement of the trip latch 98.

In order to charge the compression spring 94 in response to the closing operation of the switch blade comprising movable contact 25, there is journaled in the housing 8| a crank shaft |00 to which are fastened the crank arms |0| and |02 respectively. The crank arm 10| is disposed within the housing 8| while the crank arml |02 is disposed externally. The shaft |00 is journaled in the housing 8| in a substantially gas-tight manner. The crank arm |0| is adapted to engage the member 95 so that upon clockwise rotation of the shaft |00 the spring 94 is charged. Such clockwise rotation of the shaft |00 occurs by virtue of movement of the crank arm |02 caused by movable contact 25 engaging the portion I02a thereof during the circuit closing operation. A suitable stationary arcing contact |04 is also associated with the housing 8|, preferably integrally formed therewith, and is disposed closely adjacent to the lower end of a movable arcing contact |05, preferably in the form of a copper or aluminum tube, the lower end of which rests on the member 95 and which tube preferably extends through the bore of the insulating tube 85 and into close association with an upper stationary arcing contact |06 of annular form. The annular arcing contact |06 is illustrated as including a downwardly extending flange |06dr for threaded engagement with the insulating tube 85 and an upwardly extending flange |0612 for threaded engagement wtih a conducting tube |01 forming the upper portion of the stationary arcing horn 80 and comprising the portion having sliding engagement with the bifurcations of the movable arcing horn 3|. The conducting tube |01 is preferably provided with a vent |08 substantially identical with the vent 13 of the preceding embodiment. T he upper end of the conducting tube |01, is closed by means of a suitable cap |09 which also closes the upper end of the tube 86 housing the trip rod 81. Disposed Within the cap |09 which eiectively provides a sort of a housing is a pivotally mounted trip lever ||0 connected to the trip rod 81, preferably in the same manner as the trip latch 98 is connected thereto. The trip lever ||0 is illustrated as being mounted in the form of a crank on a suitable shaft l journaled in the cap |09 and to which is also attached a crank ||2 having a lateral projection ||3 extending outside the conducting tube |01 through an opening ||4 defined in a tubular member |01.

The lateral projection ||3 is eiectively engaged .il

by the movable arcing horn 3| both during the circuit opening and the circuit closing operatlon in the same manner as the member 65. A light spring I5 tends to hold the lever l I2 in a central position so that upward movement thereof will cause release of the trip latch 98.

In view of the detailed description included above the operation of the arrangement disclosed in Fig. 5 of the drawings will be readily under stood, and as in the preceding embodiment openhorn 3|, the trip latch 99 is released and an arc is drawn within the bore 85a. of the tube 85 and extinguished so that when an external arc gap is produced between the movable arcing horn 3| and the tubular member |01 no current will flow and no external arc will be drawn. All the arc g,

gases produced are exhausted through the vent |98 and as soon as the pressure subsides the rod |05 will fall by gravity to a position whereby the lower end rests on the member 95,

It will be apparent that there has been pro vided a simple arrangement capable of converting conventional high voltage air break switches so as to successfully interrupt high line charging currents as well as transformer magnetizing currents. disposed in an essential part of the airbreak switch specifically disclosed as the stationary arcing horn. rThe movable arcing contact associated with the interrupter moves at very high speed by virtue of its lightness and the large amount f:

of energy stored in the charged compression spring. Since this movable contact is unrestrained in its movement a long arc is drawn in a very short time and the circuit is interrupted in a cycle or less.

Furthermore this circuit interrupter is f While therehave been shown and described particular embodiments of the present invention, it is not desired that the invention be limited to the construction shown and described, for it will, of course, be obvious to those skilled in the art, that changes and modifications may be made without departing from the invention and it is therefore aimed in the appended claims to cover all such changes and modications as fall within the true spirit and scope of this invention.

What is claimed as new and desired to be secured by Letters Patent of the United States is:

l. In an isolating switch, the combination of a pair of relatively movable current carrying contacts, cooperating arcing horns associated with said contacts and separable subsequent to separation of said current carrying contacts, one of said arcing horns being slidable along the outside of the other arcing horn and in electrical contact therewith, an arc interrupting device disposed within one of said arcing horns including relatively separable arcing contacts, means responsive to relative separation of said current carrying contacts for causing current flowing through said current carrying contacts to be transferred to a path including said arcing contacts, and means for causing relative separation of said arcing contacts prior to disengagement of said arcing horns.

2. In an isolating switch, the combination of a pair of relatively movable current carrying contacts, cooperating arcing horns associated with said contacts and separable subsequent to separation of said current carrying contacts, an

arc interrupting device disposed within one of said arcing horns including relatively separable arcing contacts, means responsive to relative separation of said current carrying contacts for causing current owing through said current carrying contacts to be transferred to a path including said arcing contacts, means for causing relative separation of said arcing contacts prior to disengagement of said arcing horns, said arcing contacts automatically reclosing following disengagement of said arcing horns.

8. A switch comprising a pair of relatively movable current carrying contacts, cooperating arcing horns associated with said contacts and separable subsequent to separation of said current carrying contacts, one of said arcing horns being slidable along the outside of the other arcing horn and in electrical contact therewith, an arc interrupting device disposed within one of said arcing horns including relatively separable arcing contacts, latch control means for causing relative separation of said arcing contacts, means responsive to relative separation of said current carrying contacts for causing current iiowing through said eurent carrying contacts to be transferred to a path including said arcing contacts, means for causing relative separation of said arcing contacts prior to disengagement of said arcing horns, and means responsive to reclosing of said current carrying contacts for rendering said latch control means effective for a subsequent arc interrupting operation.

4. In an isolating switch, the combination of a pair of relatively movable current carrying contacts, cooperating arcing horns associated with said contacts and separable subsequent to separation of said current carrying contacts, one of said arcing horns being slidable along the outside of the other arcing horn and in electrical contact therewith, an arc interrupting device disposed within one of said arcing horns including relatively separable arcing contacts, energy storage means associated with said arcing contacts and adapted when released to cause relative separation of said arcing contacts, means for charging said energy storage means, latch means for holding said energy storage means in a charged condition, means responsive to relative separation of said current carrying contacts for causing current flowing through said current carrying contacts to be transferred toa path including said arcing contacts, means responsive to a predetermined relative movement between said arcing horns for releasing said latch means, and means responsive to closing of said current carrying contacts for charging said energy storage means for a subsequent circuit opening operation.

5. A switch, comprising a stationary current carrying contact having a stationary arcing horn rigidly connected thereto, a movable current carrying contact having a movable arcing horn connected thereto, means for moving said movable current carrying contact and movable arcing horns between open and closed positions, said movable arcing horn being slidable along the outside of the stationary arcing horn in electrical -contact therewith, said arcing horns being electrically engaged prior to electrical engagement of said current carrying contacts during a circuit closing operation and electrically disengaged subsequent to said current carrying contacts during a circuit opening operation, an arc interrupting device disposed within said stationary arcing horn including relatively separable arcing contacts, means responsive to rel- I:

ative separation of said current carrying contacts for causing current ilowing through said current carrying contacts to be transferred to a path including said arcing contacts, and means for causing relative separation of said arcing contacts prior to disengagement of said arcing horns. A

6. A switch, comprising a stationary current carrying contact having a stationary arcing horn rigidly connected thereto, a movable current carrying contact having a movable arcing horn connected thereto, means for moving said movable current carrying contact and movable arcing horns between open and closed positions, said movable arcinghorn being slidable along the outside of the stationary arcing horn in electrical contact therewith, said arcing horns being electrically engaged prior to electrical engagement of said current carrying contacts during a circuit closing operation and electrically disengaged subsequent to said current carrying contacts during a circuit opening operation, an arc interrupting device disposed within said stationary arcing horn including relatively separable arcing contacts, means responsive to relative separation of said current carrying contacts for causing current flowing through said current carrying contacts to be transferred to a path including said arcing contacts, a compression spring for causing relative separation of said arcing contacts, latch means for restraining said compression spring in the stressed condition, and means responsive to a predetermined relative separation of said current carrying contacts for actuating said latch means to release said compression spring.

7. A switch, comprising a stationary current carrying contact having a vertically disposed stationary arcing horn rigidly connected thereto, a movable current carrying contact having a movable arcing horn connectedthereto, means for moving said movable current carrying contact and movable arcing horns between open and closed positions, said arcing horns being electrically engaged prior to electrical engagement of said current carrying contacts during a circuit closing operation and electrically disengaged subsequent to said current carrying contacts during a circuit opening operation, an arc interrupting device disposed within said stationary arcing horn including an arc extinguishing chamber and a vertically movable rod like arcing contact movable in said chamber, means responsive to relative separation of said current carrying contacts for causing current flowing through said current carrying contacts to be transferred to a path including said arcing contacts, a vertically disposed compression spring, means for compressing said spring, the lower end of said arcing contact resting on said last mentioned means, latch means for restraining said compression spring in a stressed condition, a trip member mounted on said stationary arcing horn and actuated during the opening movement of said movable arcing horn, and means interconnecting said trip member and latch means.

8. A high voltage switch, comprising a stationary current carrying contact having a stationary arcing horn rigidly connected thereto, a movable current carrying contact having a movable arcing horn connected thereto, means for moving said movable current carrying contact and movable arcing horns between open and closed positions, said movable arcing horn being slidable along the outside of the stationary arcing horn in electrical contact therewith, said arcing horns being electrically engaged prior to electrical engagement of said current carrying contacts during a circuit closing operation and electrically disengaged subsequent to said current carrying contacts during a circuit opening operation, an arc interrupting device disposed within said stationary arcing horn including relatively separable arcing contacts, means responsive to relative separation of said current carrying contacts for causing current flowing through said current carrying contacts to be transferred to a path including said arcing contacts, releasable energy storage means for causing relative separation of said arcing contacts, latch means for rendering said means ineffective, a trip member on said stationary arcing horn actuable in response to a predetermined opening movement of said movable arcing contact, and means interconnecting said latch means and trip member.

9. In a switch, a pair of relatively movable contacts comprising a movable rod-like contact, and means for freely propelling said rod-like contact in the manner of a projectile away from the other of said contacts during a circuit interrupting operation, said rod-like contact during the interval of free propulsion thereof being bodily moved in a direction away from said last mentioned means.

10. In a switch, a vertically disposed tubular arc extinguishing chamber having inside walls formed of an insulating material capable of evolving an are extinguishing gas when subjected to the heat of an arc, a pair of relatively movable contacts comprising a movable rod-like contact disposed in said chamber, and means for freely propelling said rod-like contact in the manner of a projectile away from the other of said contacts during a circuit interrupting operation to draw an arc in said chamber, said rod-like contact during the interval of free propulsion thereof being bodily moved in a direction away from said last mentioned means.

11. In a switch, a vertically disposed tubular arc extinguishing chamber having inside walls formed of an insulating material capable of evolving an arc extinguishing gas when subjected to the heat of an arc, a pair of relatively movable contacts comprising a vertically movable rod-like contact disposed in said chamber, a compression spring having means at the upper end thereof upon which said rod-like contact rests so that upon release of the energy in said spring said rod-like contact is propelled in the manner of a projectile away from the other of said contacts and bodily away from said spring 14 to draw an arc in said chamber, and releasable means for holding said compression spring in a charged condition, the force of gravity acting on said rod-like contact causing it to fall back upon said means at the upper end of said spring.

LESTER C. HART.

REFERENCES CITED The following references are of record in the le of this patent:

UNITED STATES PATENTS Number Name Date 1,963,418 Pittman et al June 19, 1934 2,200,122 Rawlins May 7, 1940 2,239,224 Goldner Apr. 22, 1941 2,315,618 Huffstutter Apr. 6, 1943 2,458,478 Maneval Jan. 4, 1949 

